I am installing new memory modules in 2 different R710's and both have dual x5650 processors.  I installed 8 x 16gb modules per system 4 per processor. I installed in, A6-A3-A5-A2  B6-B3-B5-B2 1 machine boots show memory @128gb and running at 1333mhz and shows no signs of issues until I try to login to server 2008 R2 enterprise.  At this point it get to setting up desktop and never goes any further, no spinning icon or anything just the words.

Second machine has same install but shows that the memory is in a non optimal configuration and then finishes boot.  This is system is running ESXI and has vcenter installed with 6 virtual machines.  All machines boot and seem to run normally, however I cant access Vcenter  with the domain credentials like we normally can, I have to use ip and root username and passwords.

We return old memory to systems and everything works again.  I have never seen memory stop me from logging into a machine.  Have I installed the 16gb memory modules in the wrong slots for this to work?